Organic Small Molecules – Chemical & Biological Sensors.

 
We have developed silicon-containing small molecules, which can be modified for the detection of selective analytes, or converted to a polymeric materials for application in biological imaging and chemo- and biosensing. We have been investigating the preparation of these materials using the C-H activation reaction as a sustainable method of conducting organic synthesis.
 

Strong. Secure. Sustainable.

Sustainability is a major focus in science, especially for the preparation of polymeric materials. Our group explores synthetic methods to prepare polymers from raw materials that are cheap and/or renewable for the purpose of manufacturing high performance materials. Presently, most high-performance commercial polymers are derived from petroleum-based compounds (petrochemicals). The worldwide consumption of plastic between the years 2014 and 2020 is predicted to increase by 29%. As the world consumption of petroleum-based products increases, there is a growing concern that the world’s main energy source will be unable to meet the demands. Along with the potential depletion of fossil fuel source, is the concern for the environmental as the products produced from fossil fuel results in hazardous waste and greenhouse gas emission. As the world seeks solutions to these problems, no overarching resolution has been found. One obvious solution to this problem would be to engineer biodegradable polymers that are produced from sustainable raw materials (biomass).

One could imaging a green life cycle for these polymers that would avoid the production of hazardous waste and excess greenhouse gas pollution since they wouldn’t require combustion practices in their demise. Actually, the Biomass R&D Technical Advisory Committee commissioned by congress, proposed to replace the current U.S. petroleum consumption up to 30 % with biofuels by 2030. In this regards, lignin, which is in the second most abundant polymer on earth has been identified as a major feedstock for biofuels and chemicals. Lignin is the largest bio-based source for aromatic compounds and as such many groups, including ours are interested in building bio-based replacement polymers for petroleum-based ones.

In our lab, we design and synthesize poly(ether amides) and poly(ester amides) from lignin-derived precursors in our efforts to develop alternative thermoplastics that are capable of replacing current pertrochemical-based ones. In addition to developing these alternative thermoplastics from cheap raw materials, we endeavor to engineer time-sensitive degradable linkages within our polymers to provide enviormentally degradable materials that are environmentally benign.

Polyaniline ‘Mimic’

The field of intrinsically conducting polymers (ICP) has been a rising area of research since it was discovered that organic materials could be made to become semiconductors with conductivity high enough to be called “synthetic metals”. Large efforts have gone into the development of new conjugated polymers because of their potential applications and their excellent electronic and morphological tunability using organic synthetic methods.

Of the many different ICPs that are known, polyaniline (PANI) stands out among them due to its outstanding air and moisture stability, simple preparation technique, moderately high conductivity, high redox reversibility and low cost. PANI is one of the most used/applied ICPs known today with commercial application in printed circuit board manufacturing (final finishes, used in millions of m² every year), antistatic and electrostatic dispersive (ESD) coatings, and corrosion protection, and potential applications in many fields such as, anticorrosion coatings, supercapacitors, electronic devices as hole-injection layers, solar cells, biosensors, and toxic metal recovery.

Unfortunately, practical use of PANI is plagued by the material’s aging effect, optical and electrochemical instability, and the lack of standard/optimized deposition methods. These challenges are very difficult to overcome for PANI, and all efforts to improve PANI films have not been able to sufficiently overcome its deficiencies for many other commercial applications. We have been investigating a new series of rhodamine-based conducting polymers as potential mimic/alternative to PANI.